how to separate files for mocha-webpack

Question

What's happening is that when I run my tests, my coverage only shows bundle.js which isn't that helpful.

I have the following webpack file setup and wanted to know what I should change to make it so that each file is covered individually

webpack.config-test.js

var nodeExternals = require("webpack-node-externals")
const path = require("path")

module.exports = {
    context: path.resolve(__dirname),
    resolve: {
        extensions: [".js"],
        alias: {
            "@": path.join(__dirname, "../../src/server"),
        }
    },
    output: {
        path: "./",
        filename: "[name].js",
    },    
    target: "node", // webpack should compile node compatible code
    externals: [nodeExternals()], // in order to ignore all modules in node_modules folder
}

running the command via npm:

nyc mocha-webpack --webpack-config test/server/webpack.config-test.js --glob \"*spec.js\" test/server/unit

The output currently is:

All files  |    90.38 |    70.83 |    90.91 |     90.2 |                   |
 bundle.js |    90.38 |    70.83 |    90.91 |     90.2 |... 78,280,282,306

whereas I'm expecting the output to be

All files     |       80 |    68.75 |       80 |       80 |                   |
 functions.js |    78.79 |    68.75 |       80 |    78.79 |... 59,60,62,64,88 |
 mixin.js     |      100 |      100 |      100 |      100 | 

In the non mocha-webpack version, I also added the filename to each test, and I would like that to also happen in the webpack version. So without webpack, I run on an index.js, i.e.

index.js

const fs = require("fs")
const path = require("path")

const files = fs.readdirSync(__dirname)
files.forEach(file => 
{
    if (!file.match(/\.spec\.js$/))
        return

    console.log(file)

    describe(file, function () 
    {
        require(path.join(__dirname, file))
    })
})

which then outputs something like:

  sql.spec.js
    Some SQL tests
      ✓ should be 10

  test.spec.js
    generateRandomString
      ✓ should generate a 20 length string
      ✓ should generate a 40 length string
      ✓ should throw error for -10
      ✓ should throw error for length
    getRequiredProps
      ✓ should get prop
      ✓ should throw error
    toTime
      ✓ 1 seconds should return 1000
      ✓ 1 minutes should return 60000
      ✓ 1 hours should return 3600000
      ✓ 1 days should return 86400000

Update

There's source-mapping, but it's showing a lot more than I'd like: https://github.com/zinserjan/mocha-webpack/blob/master/docs/installation/webpack-configuration.md

------------------------------------------|----------|----------|----------|----------|-------------------|
File                                      |  % Stmts | % Branch |  % Funcs |  % Lines | Uncovered Line #s |
------------------------------------------|----------|----------|----------|----------|-------------------|
All files                                 |     78.8 |    54.72 |    87.27 |     78.7 |                   |
 .tmp/mocha-webpack/1532582562486/webpack |    95.45 |       75 |    83.33 |    95.24 |                   |
  bootstrap 4e654663ecc955703de0          |    95.45 |       75 |    83.33 |    95.24 |                49 |
 node_modules/mocha-webpack/lib           |      100 |      100 |      100 |      100 |                   |
  entry.js                                |      100 |      100 |      100 |      100 |                   |
 src/server                               |       64 |    48.65 |       70 |       64 |                   |
  db.js                                   |    45.61 |    26.32 |    45.45 |    45.61 |... 20,122,126,138 |
  functions.js                            |    84.85 |    72.22 |      100 |    84.85 |    42,58,59,60,87 |
  mixin.js                                |      100 |      100 |      100 |      100 |                   |
  mock.js                                 |      100 |      100 |      100 |      100 |                   |
 src/server/post                          |       75 |     62.5 |      100 |       75 |                   |
  maptool.js                              |       75 |     62.5 |      100 |       75 |... 41,148,158,159 |
 test/server/unit                         |    98.33 |      100 |      100 |    98.33 |                   |
  functions.spec.js                       |    96.97 |      100 |      100 |    96.97 |                67 |
  maptool.spec.js                         |      100 |      100 |      100 |      100 |                   |
  mock.spec.js                            |      100 |      100 |      100 |      100 |                   |
  sql.spec.js                             |      100 |      100 |      100 |      100 |                   |
------------------------------------------|----------|----------|----------|----------|-------------------|

How would I reduce it so that only the files being checked are outputted?

Answer 1

How would I reduce it so that only the files being checked are outputted?

It looks like even your spec files are not exluded from coverage report. Try to provide paths to the files that will be included in the coverage report in nyc config. In your package.json:

{
  ...
  "nyc": {
    "include": [
      "src/server/**/*.js"
    ],
    ...
   },
   ...
}

If it does not help try to instrument your code with instanbul-instrumenter-loader, provide paths for files to be covered in loader rule in your webpack config:

    module: {
      rules: [
        {
          test: /\.js$/,
          use: { loader: 'istanbul-instrumenter-loader' },
          include: path.resolve('../../src/server')
        }
      ]
}

and nyc default instrumenter should be disabled with instrument: false in nyc config.

UPDATE

As another solution if you are using Babel(and Vue) it make sense to instrument code with babel-plugin-istanbul it creates correct mapping (by the way I could not make istanbul-instrumenter-loader work with babel webpack configuration correctly).

I recommend to see vue-test-utils-mocha-webpack-example even you have no Vue dependency but use Babel.

Hope it helps.

Related resource: Code coverage for mocha-webpack